You don't need all those x's and (x)'s. They just get in the way. And we know they're understood. Use conditional proof or indirect proof as needed: 1. R ⊃ (T • ∼E) 2. (Q • R) ⊃ E / R ⊃ ∼Q 3. | R Assumption for Conditional proof 4. | T • ∼E 1,3, Modus Ponens 5. |~E • T 4, Commutation 6. |~E 5, Simplification 7. |~(Q • R) 2,6, Modus tollens 8. |~Q ∨ ~R 7, DeMordan's law 9. |~R ∨ ~Q 8, Commutation 10. |~~R 3, Double negation 11. |~Q 9,10, Disjunctive syllogism 12. R ⊃ ∼Q lines 3-11 Conditional proof Edwin